Gear cooling system

Abstract

Systems and methods for gear cooling. In one example, the gear cooling system includes a spray tube positioned within a central opening that is included in a first gear. The spray tube includes an oil outlet, the oil outlet is positioned within a smaller diameter section of the central opening, the smaller diameter section is axially offset from an outer toothed portion of the first gear, and the central opening includes a larger diameter section that is positioned interior to the outer toothed portion of the first gear.

The invention claimed is: 
     
       1. A gear cooling system comprising:
 a spray tube positioned within a central opening that is included in a first gear; 
 wherein the spray tube includes an oil outlet; 
 wherein the oil outlet is positioned within a first smaller diameter section of the central opening; 
 wherein the first smaller diameter section is axially offset from an outer toothed portion of the first gear; 
 wherein the central opening includes a larger diameter section that is positioned interior to the outer toothed portion of the first gear; and 
 wherein an axial length of the spray tube is larger than an axial length of the first gear. 
 
     
     
       2. The gear cooling system of  claim 1 , wherein the central opening further includes a second smaller diameter section that is positioned at an axial end of the first gear and interior to the outer toothed portion of the first gear. 
     
     
       3. The gear cooling system of  claim 1 , wherein the spray tube is in fluidic communication with an oil source. 
     
     
       4. The gear cooling system of  claim 3 , wherein the oil source is an oil pump positioned in a sump of an electric drive. 
     
     
       5. The gear cooling system of  claim 1 , wherein a diameter of the first smaller diameter section is constant along its axial length. 
     
     
       6. The gear cooling system of  claim 1 , wherein the central opening further includes an internal ridge, the first smaller diameter section being between the internal ridge and the larger diameter section. 
     
     
       7. The gear cooling system of  claim 1 , wherein a diameter of the larger diameter section is constant along its axial length. 
     
     
       8. The gear cooling system of  claim 1 , wherein the outer toothed portion is formed from multiple helical gear teeth. 
     
     
       9. The gear cooling system of  claim 1 , wherein the gear cooling system is included in an electric axle that includes a traction motor, a differential, and multiple axle shafts. 
     
     
       10. The gear cooling system of  claim 9 , wherein the electric axle is included in an all-electric vehicle. 
     
     
       11. The gear cooling system of  claim 1 , wherein the first gear meshes with a second gear. 
     
     
       12. The gear cooling system of  claim 1 , wherein the first smaller diameter section includes multiple oil channels formed as recesses in an interior surface. 
     
     
       13. A method for operation of a gear cooling system, comprising:
 flowing oil to a spray tube from an oil source; and 
 rotating a gear; 
 wherein the gear cooling system includes:
 the spray tube positioned within a central opening of the gear and including an oil outlet; 
 
 wherein the oil outlet is positioned within a first smaller diameter section of the central opening; 
 wherein the first smaller diameter section is axially offset from an outer toothed portion of the gear; 
 wherein the central opening includes a larger diameter section that is positioned interior to the outer toothed portion of the gear; and 
 wherein an axial length of the spray tube is larger than an axial length of the gear. 
 
     
     
       14. The method of  claim 13 , wherein the central opening further includes a second smaller diameter section that is positioned at an axial end of the gear and interior to the outer toothed portion of the gear and wherein oil exits the gear cooling system through the second smaller diameter section. 
     
     
       15. An internal gear cooling system comprising:
 a spray tube positioned within a central opening in a gear; 
 wherein the spray tube includes an oil outlet; 
 wherein the oil outlet is positioned within a first smaller diameter section of the central opening; 
 wherein the first smaller diameter section is axially offset from an outer toothed portion of the gear; 
 wherein the central opening includes a larger diameter section that is positioned interior to the outer toothed portion of the gear; 
 wherein the central opening further includes a second smaller diameter section that is positioned at an axial end of the gear and interior to the outer toothed portion of the gear; 
 wherein oil sequentially flows through the first smaller diameter section, the larger diameter section, and the second smaller diameter section; and 
 wherein an axial length of the spray tube is larger than an axial length of the gear. 
 
     
     
       16. The internal gear cooling system of  claim 15 , wherein the internal gear cooling system is included in a gearbox of an electric axle. 
     
     
       17. The internal gear cooling system of  claim 15 , wherein the first smaller diameter section includes multiple spiral oil channels.